Slit block



Patented Nov. 20, 1928.

UNITED STATES PATENT orrlcsy RICHARD HALPENNY, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR T DE FOB/EST PHONOFILM CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

SLIT BLOCK.

Application filed March 14, 1927. Serial No. 175,067

This invention relates broadly to a phonofilm apparatus.

One of the objects of this invention is the provision of a new means for use in conjunction with slit blocks as used on the projection apparatus of talking motion picture machines for preventing the clogging of the light slit by dust and othcr foreign materials. A further object of this invention is the provision of cleaning grooves formed in the slit block surface and associated with the light aperture, so as to remove dust, dirt and other particles from the surface of the film, so that they will not clog the light aperture.

These and many other objects are sought byt means of the construction disclosed hereina er.

This invention resides substantially in the combination, construction, arrangement and 0 relative location of parts as will be described below.

Referring to the drawings,

Figurel is a front elevational view of a slit block.

Figure 2 is an enlarged cross-sectional view taken on the line 22 of Figure 1.

This invention relates in particular to improvements in slit blocks of the type shown and described inthe copending application of John Kaufman, Serial No. 151,042, filed November 27 1926.

In the practical operation of sound reproducing attachments for motion picture projectures, it has been found that the very small light slit or aperture employed in connection with the sound record portion of the film has a tendency to rapidly become ineffective because of the clogging of the light slit or aperture, by dust or otherparticles which adhere to the surface of the film.

Many devices have been provided for removing the dust and dirt from the film before it passes down over the surface of the slit block, but in actual operation it has been found that dust and dirt is not effectively removed from the film and as a result the light sl t rapidly clogs and its efiiciency is greatly impaired. By means of the construction described below, I have been able to produce a simple modification of the present form of slit block by means of which the clogging of the light aperture is prevented.

light aperture 2 overhangs the foremost por- The slit block is shown generally at 1 having a light aperture extending therethrough at 2. A recess or chamber 3 is formed in the slit 5? block and extends at right angles to the aperture 2 and intersects it. The light slit is shown at 4 and is formed by means of segmental members 10 and 11 as has been clearly disclosed in the above cited application, and which forms no part of this invention. The slit 4 is protected by means of a transparent covering 5. which may be made of any suitable light transmitting material. The face of the slit block directly below the light apero3 ture 2 is ground or cut away at 6 to form a re cess of gradually decreasing cross-section. Formed in the slit block and above the light aperture is an inclined groove 7, and another inclined groove is shown at8 which extends into and terminates at the lower end of the recess 6.

It will be noted that the edge formed by the intersection of the surface of block 1 and the '15 tion of the slit covering 5, so that the fihn which passes down over the face of the slit block will pass the light slit and its protects ing cover in close proximity thereto, but just out of contact therewith. This prevents wearing and scouring of the covering 5, as well as scratching of the film.

In operation the dust and dirt on the surface of the film as it passes over the face of the slit block collects in the grooves 6, 7 and 8 8 and is gradually forced out of the lower ends of the groove by reason of the movement of the film over the face of the slit block. By reason of the particular construction and arrangement of the groove, it is evident that dust cannot collect in front of the light slit, to reduce its light transmitting efliciency'.

I am aware that some changes in the details of construction and relative arrangement of parts will occur to those skilled in this art and I prefer therefore to be limited only as required by the following claims. 7

What I seek to secure by United States Letters Patent is:

1. The combination with a split block having a light aperture of grooves formed in said block for cleaning the film as it passes over said block. 7

2. The combination with a slit block having a light aperture of inclined grooves formed on the face of said block. r

3. The combination with aslit block having a light aperture of a groove above Said light aperture over which the film passes to remove dirt from the surface thereof.

4. The combination with a slit block having a light aperture of grooves formed in said block above and below said aperture for removing dirt from the surface of the film which passes thereover.

5. The combination with a slit block having alight aperture of inclined grooves formed in said block above and below said a erture.

6. The combination with a slit iilock having a light aperture of grooves formed in said block one of said grooves extending into said aperture.

7 The combination with a slit block having a light aperture of a depression formed in said block and extending into said aperture and an inclined groove formed in said block above and below said light aperture.

8. The combination with a slit block having a light aperture of a converging depression extending to said light aperture and an inclined groove formed in said block above and below said aperture, said lower groove terminating in said depression.

9. The combination with a slit block having a plurality of cleaning grooves of a light aperture and a slit forming member in said aperture said slit forming member being set back from the slit block surface so as to be out of contact with the film passing over the slit block.

10; The combination with a slit block having a plurality of cleaning grooves of a light aperture, a slit forming member in said aperture and a transparent protecting member for said slit, said slit forming member being mounted in said light aperture so as to be generally out of contact with the film passing over the slit block.

11. The combination with a slit block having a light aperture, .a recess connecting with said aperture, a plurality of grooves formed in said block and arranged above and below said aperture of a slit forming member in said recess, at least one of said grooves extending into said aperture.

.In testimon whereof I have hereunto set my hand on this 9th day of March A. D., 1927.

RICHARD HALPENN Y. 

